PROCESS FOR PRODUCING 5-HYDROXYMETHYLFURFURAL IN THE PRESENCE OF AN ORGANIC DEHYDRATION CATALYST AND A CHLORIDE SOURCE

Abstract

The invention relates to a novel process for converting a feedstock comprising at least one sugar into 5-hydroxymethylfurfural, wherein said feedstock is brought into contact with one or more organic dehydration catalysts and one or more chloride sources in the presence of at least one aprotic polar solvent alone or as a mixture, at a temperature of between 30 C. and 200 C., and at a pressure of between 0.1 MPa and 10 MPa.

Claims

1. A process for converting a feedstock comprising at least one sugar into 5-hydroxymethylfurfural, wherein said feedstock is brought into contact with at least one organic dehydration catalyst independently chosen from homogeneous and heterogeneous organic Brnsted acids, and at least one chloride source of general formula (III) Q.sub.yCl.sub.z in the presence of at least one aprotic polar solvent, at a temperature of between 30 C. and 200 C. and a pressure of between 0.1 and 10 MPa, wherein Q is chosen from hydrogen, an alkali or alkaline-earth metal chosen from groups 1 and 2 of the periodic table or an organic cation chosen from the ammonium, phosphonium and guanidinium family y is between 1 and 10, z is between 1 and 10.

2. The process as claimed in claim 1, wherein the feedstock is chosen from oligosaccharides and monosaccharides, alone or as a mixture.

3. The process as claimed in claim 1, wherein the feedstock is chosen from sucrose, lactose, maltose, isomaltose, inulobiose, melibiose, gentiobiose, trehalose, cellobiose, cellotriose, cellotetraose and oligosaccharides resulting from the hydrolysis of said polysaccharides resulting from the hydrolysis of starch, inulin, cellulose or hemicellulose, alone or as a mixture.)

4. The process as claimed in claim 1, wherein the dehydration catalyst is an organic Brnsted acid chosen from the organic acids of general formulae RCOOH, R SO.sub.2H, R SO.sub.3H, (RSO.sub.2)NH, (RO).sub.2PO.sub.2H, ROH, wherein R is chosen from alkyl and alkanol groups comprising from 1 to 20 carbon atoms, aryl and heteroaryl groups preferably comprising between 4 and 20 carbon atoms, and a hydrogen when the acid chosen corresponds to general formula R COOH.

5. Process as claimed in claim 1, wherein the dehydration catalyst is a heterogeneous organic Brnsted acid chosen from sulfonic acid resins, carbons functionalized with sulfonic and/or carboxylic groups, and silicas functionalized with sulfonic and/or carboxylic groups.

6. The process as claimed in claim 1, wherein the chloride source is chosen from the compounds wherein Q is an alkali or alkaline-earth metal chosen from Li, Na, K, Rb, Cs, Fr, Mg, Ca, Sr and Ba.

7. The process as claimed in claim 1, wherein the chloride source is an organic cation of the ammonium family chosen from the compounds corresponding to general formula (IIIa) ##STR00005## wherein R.sub.1 to R.sub.4, which may be identical or different, are independently chosen from alkyl groups comprising between 1 and 20 carbon atoms, optionally substituted with at least one group chosen from the following list: aldehyde C(O)H, ketone C(O)R, carboxylic acid COOH, ester COOR, hydroxymethyl CH.sub.2OH, ether CH.sub.2OR, halogenated CH.sub.2X, aryl groups comprising between 5 and 20 carbon atoms, optionally substituted with at least one group chosen from the following list: aldehyde C(O)H, ketone C(O)R, carboxylic acid COOH, ester COOR, hydroxymethyl CH.sub.2OH, ether CH.sub.2OR, halogenated CH.sub.2X, wherein R is an alkyl group comprising from 1 to 15 carbon atoms, and X is chosen from Cl, Br, I.

8. The process as claimed in claim 1, wherein the chloride source is an organic cation of the guanidium family chosen from the compounds corresponding to general formula (IIIb) ##STR00006## wherein the groups R.sub.5 to R.sub.10, which may be identical or different, are independently chosen from alkyl groups comprising between 1 and 20 carbon atoms, and aryl groups comprising between 5 and 20 carbon atoms.

9. The process as claimed in claim 1, wherein the chloride source is an organic cation of the phosphonium family chosen from the compounds corresponding to general formula (IIIc) ##STR00007## wherein R.sub.11 to R14, which may be identical or different, are independently chosen from alkyl groups, comprising between 1 and 20 carbon atoms, aryl groups, comprising between 5 and 20 carbon atoms, phosphazene groups of general formula ##STR00008## wherein R.sub.15 is an alkyl group comprising from 1 to 10 carbon atoms, and q an integer between 0 and 10.

10. The process as claimed in claim 1, wherein the aprotic polar solvent(s) are chosen from all the aprotic polar solvents of which the dipole moment expressed in Debye (D) is greater than or equal to 2.00.

11. The process as claimed in claim 1, wherein at least one aprotic polar solvent, alone or as a mixture, is chosen from pyridine, butan-2-one, acetone, acetic anhydride, N,N,N,N-tetramethylurea, benzonitrile, acetonitrile, methyl ethyl ketone, propionitrile, hexamethylphosphoramide, nitrobenzene, nitromethane, N,N-dimethylformamide, N,N-dimethylacetamide, sulfolane, N-methylpyrrolidone, dimethyl sulfoxide, propylene carbonate and -valerolactone.

12. The process as claimed in claim 1, wherein the feedstock is introduced into the process in a weight ratio of the solvent to the feedstock (solvent/feedstock) of between 0.1 and 200.

13. The process as claimed in claim 1, wherein the organic dehydration catalyst(s) are introduced into the reaction chamber in a weight ratio of the feedstock to the catalyst (feedstock/catalyst) of between 1 and 1000.

14. The process as claimed in claim 1, wherein the chloride source(s) are introduced into the reaction chamber in a weight ratio of the feedstock to the chloride source(s) (feedstock/chloride source(s)) of between 1 and 1000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0027] Within the meaning of the present invention, the various embodiments presented can be used alone or in combination with one another, without any limit to the combinations.

[0028] The feedstock

[0029] The feedstock treated in the process according to the invention is a feedstock comprising at least one sugar, preferably chosen from oligosaccharides and monosaccharides, alone or as a mixture.

[0030] The term monosaccharide denotes the compounds corresponding to the general formula (Ia) C.sub.6(H.sub.2O).sub.6 or C.sub.6H.sub.12O.sub.6. Preferably, the monosaccharides are chosen from glucose, mannose and fructose, alone or as a mixture.

[0031] The term oligosaccharide denotes [0032] the compounds having the empirical formula (Ib) C.sub.6nH.sub.10n+2O.sub.5n+1wherein n is an integer between 1 and 10, the monosaccharide units making up said oligosaccharide being identical or different, and [0033] the compounds having the empirical formula (Ic) (C.sub.6mH.sub.10+2O.sub.5m+1)(C.sub.5pH.sub.8p+2O.sub.4p+1) wherein m and p are independently integers between 1 and 10, the monosaccharide units making up said oligosaccharide being identical or different.

[0034] The oligosaccharides are preferably chosen from hexose oligomers or oligomers of pentoses and hexoses, preferably from hexose oligomers. They can be obtained by partial hydrolysis of polysaccharides from renewable resources such as starch, inulin, cellulose or hemicellulose, optionally from lignocellulosic biomass. Steam explosion of lignocellulosic biomass is a process of partial hydrolysis of the cellulose and hemicellulose contained in lignocellulosic biomass, producing a stream of oligo- and monosaccharides.

[0035] Preferably, the oligosaccharides are chosen from sucrose, lactose, maltose, isomaltose, inulobiose, melibiose, gentiobiose, trehalose, cellobiose, cellotriose, cellotetraose and oligosaccharides resulting from the hydrolysis of said polysaccharides resulting from the hydrolysis of starch, inulin, cellulose or hemicellulose, alone or as a mixture.

[0036] Preferably, the feedstock is chosen from cellobiose, fructose and glucose, alone or as a mixture. Very preferably, said feedstock is chosen from fructose and glucose, alone or as a mixture.

[0037] The Dehydration Catalysts

[0038] In accordance with the invention, said feedstock is brought into contact in the process with at least one organic dehydration catalyst chosen from homogeneous or heterogeneous organic Brnsted acids, capable of catalyzing the dehydration of the feedstock to 5-hydroxymethylfurfural.

[0039] Preferably, the homogeneous organic Brnsted acid catalysts are chosen from the organic acids of general formulae RCOOH, RSO.sub.2H, RSO.sub.3H, (RO.sub.2)NH, (RO).sub.2PO.sub.2H, ROH, wherein R is chosen from the: [0040] alkyl groups, preferably comprising between 1 and 15 carbon atoms, preferably between 1 and 10, and preferably between 1 and 6, which are unsubstituted or substituted with at least one substituent chosen from a hydroxyl, an amine, a nitro, a halogen, preferably fluorine, and an alkyl halide, [0041] alkenyl groups which are unsubstituted or substituted with at least one group chosen from a hydroxyl, an amine, a nitro, an oxo, a halogen, preferably fluorine, and an alkyl halide, [0042] aryl groups, preferably comprising from 5 to 20 carbon atoms, preferably between 5 and 15 carbon atoms and preferably between 6 and 12 carbon atoms, which are unsubstituted or substituted with a substituent chosen from a hydroxyl, an amine, a nitro, an oxo, a halogen, preferably fluorine, and an alkyl halide, [0043] heteroaryl groups, preferably comprising between 4 and 15 carbon atoms and preferably between 4 and 12 carbon atoms, which are unsubstituted or substituted with a substituent chosen from a hydroxyl, an amine, a nitro, an oxo, a halogen, preferably fluorine, and an alkyl halide,

[0044] When the catalysts of organic Brnsted acid type are chosen from the organic acids of general formulae RCOOH, R can also be a hydrogen.

[0045] Preferably, the organic Brnsted acids are chosen from formic acid, acetic acid, trifluoroacetic acid, lactic acid, levulinic acid, methanesulfinic acid, methanesulfonic acid, trifluoromethanesulfonic acid, bis(trifluoromethanesulfonyl)amine, benzoic acid, para-toluenesulfonic acid, 4-biphenylsulfonic acid, diphenyl phosphate, and 1,1-binaphthyl-2,2-diyl hydrogen phosphate. A very preferred homogeneous organic Brnsted acid catalyst is chosen from methanesulfonic acid (CH.sub.3SO.sub.3H) and trifluoromethanesulfonic acid (CF.sub.3SO.sub.3H).

[0046] The heterogeneous Brnsted acid catalysts are chosen from sulfonic acid resins (such as for example Amberlyst 15, 16, 35 or 36, Dowex 50 WX2, WX4 or WX8, Nafion PFSA NR-40 or NR-50, Aquivion PFSA PW 66, 87 or 98), carbons functionalized with sulfonic and/or carboxylic groups, and silicas functionalized with sulfonic and/or carboxylic groups. Preferably, the heterogeneous organic Brnsted acid catalyst is chosen from sulfonic acid resins.

[0047] The Chloride Sources

[0048] In accordance with the invention, in combination with the organic dehydration catalyst(s) defined above, said feedstock is brought into contact in the process according to the invention with one or more chloride sources of general formula (III) Q.sub.yCI.sub.Z wherein [0049] Q is chosen from hydrogen, an alkali or alkaline-earth metal chosen from groups 1 and 2 of the periodic table or an organic cation chosen from the ammonium, phosphonium and guanidinium family. [0050] y is between 1 and 10, preferably between 1 and 5 and preferably between 1 and 2; [0051] z is between 1 and 10, preferably between 1 and 5 and preferably between 1 and 2.

[0052] Preferably, Q is a cation chosen from H, Li, Na, K, Rb, Cs, Fr, Mg, Ca, Sr and Ba, more preferably from H, Li, Na, K, Cs, Mg, Ca and Ba, and very preferably from H, Li, Na, K, Mg and Ca.

[0053] In the case where Q is an organic cation chosen from the ammonium family, the chloride source is chosen from the compounds corresponding to general formula (IIIa)

##STR00001##

wherein R.sub.1 to R.sub.4, which may be identical or different, are independently chosen from [0054] alkyl groups comprising from 1 to 20 carbons, optionally substituted with at least one group chosen from the following list: aldehyde C(O)H, ketone C(O)R, carboxylic acid COOH, ester COOR, hydroxymethyl CH.sub.2OH, ether CH.sub.2OR, halogenated CH.sub.2X with X=Cl, Br, I, [0055] aryl groups comprising from 5 to 20 carbons, optionally substituted with at least one group chosen from the following list: aldehyde C(O)H, ketone C(O)R, carboxylic acid COOH, ester COOR, hydroxymethyl CH.sub.2OH, ether CH.sub.2OR, halogenated CH.sub.2X with X=Cl, Br, I, [0056] wherein R is an alkyl group comprising from 1 to 15 carbon atoms, preferably from 1 to 10 and preferably from 1 to 6.

[0057] Preferably, the groups R.sub.1 to R.sub.4, which may be identical or different, preferably linear, are independently chosen from alkyl groups preferably comprising between 1 and 15 carbon atoms, preferably between 1 and 10, preferably between 1 and 8, preferably between 1 and 6, and preferably from 1 to 4 carbon atoms.

[0058] Preferably, said groups R1 to Ra are chosen from alkyls substituted with at least one group chosen from OH and COOH.

[0059] Preferably, said groups R.sub.1 to R.sub.4 are independently chosen from n-butyl, methyl, n-octyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, CH.sub.2COOH, CH.sub.2CH.sub.2COOH and CH.sub.2CH.sub.2CH.sub.2COOH groups, preferably from the methyl, hydroxyethyl and CH.sub.2CH.sub.2COOH groups.

[0060] Very preferably, the ammoniums are chosen from trioctylmethylammonium chloride ([CH.sub.3(CH.sub.2).sub.7).sub.3(CH.sub.3)N.sup.+Cl.sup.]), choline chloride ([(CH.sub.3).sub.3NCH.sub.2CH.sub.2OH).sup.+Cl.sup.]), betaine chloride ([((CH.sub.3).sub.3NCH.sub.2COOH).sup.30 Cl.sup.]), and tetramethylammonium chloride ([(CH.sub.3).sub.4N.sup.+Cl.sup.]).

[0061] In the case where Q is an organic cation chosen from the guanidinium chloride family, the chloride source is chosen from the compounds corresponding to general formula (IIIb)

##STR00002##

wherein the groups R.sub.5 to R.sub.10, which may be identical or different, are independently chosen from hydrogen, and alkyl and aryl groups.

[0062] Preferably, the groups R.sub.5 to R.sub.10, which may be identical or different, are chosen from hydrogen, alkyl groups, which are preferably linear, comprising from 1 to 15 carbon atoms, preferably from 1 to 10 carbon atoms and preferably from 1 to 6 carbon atoms.

[0063] Preferably, the groups R.sub.5 to R.sub.10, which may be identical or different, are chosen from aryl groups comprising between 5 and 20 carbon atoms.

[0064] Very preferably, the groups R.sub.5 to R.sub.10, which may be identical or different, are independently chosen from hydrogen, and methyl, ethyl, propyl and butyl groups.

[0065] Preferably, in the case where Q is an organic cation chosen from the guanidinium family, the chloride source is guanidinium chloride and hexamethylguanidinium chloride.

[0066] In the case where Q is an organic cation chosen from the phosphonium family, the chloride source is chosen from the compounds corresponding to general formula (IIIc)

##STR00003##

wherein R.sub.11 to R.sub.14, which may be identical or different, are independently chosen from alkyl groups, aryl groups and phosphazene groups of general formula (IIId)

##STR00004##

wherein R.sub.15 is an alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5, and q is an integer between 0 and 10.

[0067] Preferably, R.sub.11 to R.sub.14, which may be identical or different, are chosen from alkyl groups, which are preferably linear, comprising from 1 to 15 carbon atoms, preferably between 1 and 10 carbon atoms and preferably from 1 to 6 carbon atoms.

[0068] Preferably, the groups R.sub.11 to R.sub.14, which may be identical or different, are chosen from [0069] a phosphazene group characterized by R.sub.15=methyl and q=1, [0070] a methyl, ethyl, n-propyl, n-butyl group.

[0071] Preferably, in the case where Q is an organic cation chosen from the phosphonium family, the chloride source is tetraethylphosphonium chloride and tetra(n-butyl)phosphonium chloride.

[0072] Advantageously, the use of a chloride source in a conversion process in accordance with the invention makes it possible to limit the formation of unwanted by-products such as the products of the carboxylic acid, ester, ether and humin family.

[0073] Conversion Process

[0074] In accordance with the invention, the process for converting the feedstock comprising at least one sugar is carried out in a reaction chamber in the presence of at least one solvent, said solvent being an aprotic polar solvent or a mixture of aprotic polar solvents, at a temperature of between 30 C. and 200 C., and at a pressure between 0.1 MPa and 10 MPa.

[0075] The process is therefore carried out in a reaction chamber comprising at least one aprotic polar solvent and wherein said feedstock is placed in the presence of one or more dehydration catalysts and one or more chloride sources.

[0076] In accordance with the invention, the process is performed in the presence of at least one solvent, said solvent being an aprotic polar solvent or a mixture of aprotic polar solvents.

[0077] The aprotic polar solvents are advantageously chosen from all the aprotic polar solvents of which the dipole moment expressed in Debye (D) is greater than or equal to 2.00. Preferably, the aprotic polar solvents are chosen from pyridine (2.37), butan-2-one (5.22), acetone (2.86), acetic anhydride (2.82), N,N,N,N-tetramethylurea (3.48), benzonitrile (4.05), acetonitrile (3.45), methyl ethyl ketone (2.76), propionitrile (3.57), hexamethylphosphoramide (5.55), nitrobenzene (4.02), nitromethane (3.57), N,N-dimethylformamide (3.87), N,N-dimethylacetamide (3.72), sulfolane (4.80), N-methylpyrrolidone (4.09), dimethyl sulfoxide (3.90), propylene carbonate (4.94) and y-valerolactone (4.71) alone or as a mixture.

[0078] Preferably, the aprotic polar solvents are advantageously chosen from acetone, N,N-dimethylformamide, N,N-dimethylacetamide, sulfolane, N-methylpyrrolidone, dimethyl sulfoxide, propylene carbonate and y-valerolactone alone or as mixture.

[0079] Preferably, the aprotic polar solvents are advantageously chosen from N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide and -valerolactone alone or as a mixture. Very preferably, the solvent is dimethyl sulfoxide.

[0080] Preferably, said process according to the invention is performed at a temperature of between 40 C. and 175 C., preferably between 50 and 120 C., preferably between 60 and 100 C. and very preferably between 65 and 90 C., and at a pressure between 0.1 MPa and 8 MPa and preferably between 0.1 and 5 MPa.

[0081] Generally the process can be performed according to different embodiments. Thus, the process can advantageously be carried out batchwise or continuously. The process can be carried out in a closed reaction chamber or in a semi-open reactor.

[0082] The organic dehydration catalyst(s) are introduced into the reaction chamber in an amount corresponding to a feedstock/catalyst(s) weight ratio of between 1 and 1000, preferably between 1 and 500, preferably between 1 and 200, preferably between 1 and 150.

[0083] The chloride source(s) are introduced into the reaction chamber in an amount corresponding to a feedstock/chloride source(s) weight ratio of between 1 and 1000, preferably between 1 and 800, preferably between 1 and 500, preferably between 1 and 400.

[0084] The feedstock is introduced into the process in an amount corresponding to a solvent/feedstock weight ratio of between 0.1 and 200, preferably between 0.3 and 100 and more preferentially between 1 and 50.

[0085] If a continuous process is chosen, the weight hourly space velocity (flow rate of feedstock by weight/weight of catalyst(s)) is between 0.01 and 10 h.sup.1, preferably between 0.02 and 5 h.sup.1, preferably between 0.03 and 2 h.sup.1.

[0086] At the end of the reaction, the dehydration catalyst and the chloride source can be easily recovered by precipitation, distillation, extraction or washing.

[0087] The Products Obtained and the Method of Analysis Thereof

[0088] The product selectively obtained my means of the conversion process according to the invention is 5-hydroxymethylfurfural (5-HMF).

[0089] At the end of the reaction carried out in the process according to the invention, the reaction medium is analyzed by gas chromatography (GC) to determine the 5-HMF content in the presence of an internal standard, and by ion chromatography to determine the conversion of the feedstock in the presence of an external standard and to quantify the unwanted products such as levulinic acid and formic acid. The humins are quantified by difference in carbon balance with the carbon initially introduced.

EXAMPLES

[0090] The examples below illustrate the invention without limiting the scope thereof.

[0091] In the examples below, the glucose and fructose used as feedstock are commercially available and used without further purification.

[0092] The methanesulfonic acid denoted CH.sub.3SO.sub.3H in the examples is commercially available and used without further purification.

[0093] The methanesulfonic acid denoted CH.sub.3SO.sub.3H, the lithium chloride denoted LiCI, the potassium chloride denoted KCl, the lithium bromide denoted LiBr, the lithium fluoride denoted LiF, the choline chloride denoted ChCl, the betaine chloride denoted BetC, and the tetramethylammonium chloride denoted TMACl, in the examples below are commercially available and used without additional purification.

[0094] The dimethyl sulfoxide, denoted DMSO in the examples, used as aprotic polar solvent, is commercially available and used without further purification.

[0095] For examples 1 to 8 of conversion of sugars into 5-HMF, the molar yield of 5-HMF is calculated by the ratio between the number of moles of 5-HMF obtained and the number of moles of sugar feedstock used.

Comparative Example 1: Fructose Conversion using Methanesulfonic Acid Alone in DMSO (Not in Accordance with the Invention)

[0096] The methanesulfonic acid (0.018 g, 0.19 mmol) is added to a solution of fructose (2.0 g, 11.10 mmol) in DMSO (20 g). The feedstock/catalyst weight ratio is 111. The solvent/feedstock weight ratio is 10. The reaction medium is then stirred at 70 C. at 0.1 MPa for 6 h. The conversion of fructose into 5-HMF is monitored by regularly taking samples of an aliquot of solution which is instantly cooled to 0 C., redissolved in water and checked by gas chromatography, and by ion chromatography. The molar yield of 5-HMF after 6 h is 67%. The yield of unwanted humins is 26%.

Comparative Example 2: Fructose Conversion using Lithium Chloride Alone in DMSO (Not in Accordance with the Invention)

[0097] The lithium chloride (0.008 g, 0.19 mmol) is added to a solution of fructose (2.0 g, 11.10 mmol) in DMSO (20 g). The feedstock/catalyst weight ratio is 111. The solvent/feedstock weight ratio is 10. The reaction medium is then stirred at 70 C. at 0.1 MPa for 6 h. The conversion of fructose into 5-HMF is monitored by regularly taking samples of an aliquot of solution which is instantly cooled to 0 C., redissolved in water and checked by gas chromatography. The molar yield of 5-HMF after 6 h is 0%.

Example 3: Fructose Conversion using Potassium Chloride Alone in DMSO (Not in Accordance with the Invention)

[0098] The potassium chloride (0.014 g, 0.19 mmol) is added to a solution of fructose (2.0 g, 11.10 mmol) in DMSO (20 g). The feedstock/catalyst weight ratio is 111. The solvent/feedstock weight ratio is 10. The reaction medium is then stirred at 70 C. at 0.1 MPa for 6 h. The conversion of fructose into 5-HMF is monitored by regularly taking samples of an aliquot of solution which is instantly cooled to 0 C., redissolved in water and checked by gas chromatography, and by ion chromatography. The molar yield of 5-HMF after 6 h is 0%.

Example 4: Fructose Conversion using Methanesulfonic Acid and Lithium Chloride in DMSO (in Accordance with the Invention)

[0099] The methanesulfonic acid (0.018 g, 0.19 mmol) and the lithium chloride (0.008 g, 0.19 mmol) are added to a solution of fructose (2.0 g, 11.10 mmol) in DMSO (20 g). The feedstock/catalyst weight ratio is 111. The feedstock/chloride source weight ratio is 250. The solvent/feedstock weight ratio is 10. The reaction medium is then stirred at 70 C. at 0.1 MPa for 6 h. The conversion of fructose into 5-HMF is monitored by regularly taking samples of an aliquot of solution which is instantly cooled to 0 C., redissolved in water and checked by gas chromatography, and by ion chromatography. The molar yield of 5-HMF after 6 h is 79%. The yield of unwanted humins is 12%.

Example 5: Fructose Conversion using Methanesulfonic Acid and Potassium Chloride in DMSO (in Accordance with the Invention)

[0100] The methanesulfonic acid (0.018 g, 0.19 mmol) and the potassium chloride (0.014 g, 0.19 mmol) are added to a solution of fructose (2.0 g, 11.10 mmol) in DMSO (20 g). The feedstock/catalyst weight ratio is 111. The feedstock/chloride source weight ratio is 140. The solvent/feedstock weight ratio is 10. The reaction medium is then stirred at 70 C. at 0.1 MPa for 6 h. The conversion of fructose into 5-HMF is monitored by regularly taking samples of an aliquot of solution which is instantly cooled to 0 C., redissolved in water and checked by gas chromatography, and by ion chromatography. The molar yield of 5-HMF after 6 h is 75%. The yield of unwanted humins is 15%.

Example 6: Fructose Conversion using Methanesulfonic Acid and Choline Chloride in DMSO (in Accordance with the Invention)

[0101] The methanesulfonic acid (0.018 g, 0.19 mmol) and the choline chloride (0.027 g, 0.19 mmol) are added to a solution of fructose (2.0 g, 11.10 mmol) in DMSO (20 g). The feedstock/catalyst weight ratio is 111. The feedstock/chloride source weight ratio is 74. The solvent/feedstock weight ratio is 10. The reaction medium is then stirred at 70 C. at 0.1 MPa for 6 h. The conversion of fructose into 5-HMF is monitored by regularly taking samples of an aliquot of solution which is instantly cooled to 0 C., redissolved in water and checked by gas chromatography, and by ion chromatography. The molar yield of 5-HMF after 6 h is 78%. The yield of unwanted humins is 12%.

Example 7: Fructose Conversion using Methanesulfonic Acid and Betaine Chloride in DMSO (in Accordance with the Invention)

[0102] The methanesulfonic acid (0.018 g, 0.19 mmol) and the choline chloride (0.029 g, 0.19 mmol) are added to a solution of fructose (2.0 g, 11.10 mmol) in DMSO (20 g). The feedstock/catalyst weight ratio is 111. The feedstock/chloride source weight ratio is 69. The solvent/feedstock weight ratio is 10. The reaction medium is then stirred at 70 C. at 0.1 MPa for 6 h. The conversion of fructose into 5-HMF is monitored by regularly taking samples of an aliquot of solution which is instantly cooled to 0 C., redissolved in water and checked by gas chromatography, and by ion chromatography. The molar yield of 5-HMF after 6 h is 80%. The yield of unwanted humins is 10%.

Example 8: Fructose Conversion using Methanesulfonic Acid and Tetramethylammonium Chloride in DMSO (in Accordance with the Invention)

[0103] The methanesulfonic acid (0.018 g, 0.19 mmol) and the tetramethylammonium chloride (0.021 g, 0.19 mmol) are added to a solution of fructose (2.0 g, 11.10 mmol) in DMSO (20 g). The feedstock/catalyst weight ratio is 111. The feedstock/chloride source weight ratio is 95. The solvent/feedstock weight ratio is 10. The reaction medium is then stirred at 70 C. at 0.1 MPa for 6 h. The conversion of fructose into 5-HMF is monitored by regularly taking samples of an aliquot of solution which is instantly cooled to 0 C., redissolved in water and checked by gas chromatography, and by ion chromatography. The molar yield of 5-HMF after 6 h is 80%. The yield of unwanted humins is 10%.

Comparative Example 9: Fructose Conversion using Methanesulfonic Acid and Lithium Bromide in DMSO (Not in Accordance with the Invention)

[0104] The methanesulfonic acid (0.018 g, 0.19 mmol) and the lithium chloride (0.016 g, 0.19 mmol) are added to a solution of fructose (2.0 g, 11.10 mmol) in DMSO (20 g). The feedstock/catalyst weight ratio is 111. The feedstock/bromide source weight ratio is 125. The solvent/feedstock weight ratio is 10. The reaction medium is then stirred at 70 C. at 0.1 MPa for 6 h. The conversion of fructose into 5-HMF is monitored by regularly taking samples of an aliquot of solution which is instantly cooled to 0 C., redissolved in water and checked by gas chromatography, and by ion chromatography. The molar yield of 5-HMF after 6 h is 63%. The yield of unwanted humins is 32%.

Comparative Example 10: Fructose Conversion using Methanesulfonic Acid and Lithium Fluoride in DMSO (Not in Accordance with the Invention)

[0105] The methanesulfonic acid (0.018 g, 0.19 mmol) and the lithium fluoride (0.005 g, 0.19 mmol) are added to a solution of fructose (2.0 g, 11.10 mmol) in DMSO (20 g). The feedstock/catalyst weight ratio is 111. The feedstock/fluoride source weight ratio is 400. The solvent/feedstock weight ratio is 10. The reaction medium is then stirred at 70 C. at 0.1 MPa for 6 h. The conversion of fructose into 5-HMF is monitored by regularly taking samples of an aliquot of solution which is instantly cooled to 0 C., redissolved in water and checked by gas chromatography, and by ion chromatography. The molar yield of 5-HMF after 6 h is 0%.

TABLE-US-00001 TABLE 1 Dehydration Unwanted products Example Feedstock catalyst Chloride source 5-HMF yield (%) yield (%) 1 Fructose CH.sub.3SO.sub.3H 67 Humins 26 (not in accordance with the invention) 2 Fructose LiCl 0 (not in accordance with the invention) 3 Fructose KCl 0 (not in accordance with the invention) 4 Fructose CH.sub.3SO.sub.3H LiCl 79 Humins 12 (in accordance with the invention) 5 Fructose CH.sub.3SO.sub.3H KCl 75 Humins 15 (in accordance with the invention) 6 Fructose CH.sub.3SO.sub.3H ChCl 78 Humins 12 (in accordance with the invention) 7 Fructose CH.sub.3SO.sub.3H BetCl 80 Humins 10 (in accordance with the invention) 8 Fructose CH.sub.3SO.sub.3H TMACl 80 Humins 10 (in accordance with the invention) 9 Fructose CH.sub.3SO.sub.3H LiBr 63 Humins 32 (not in accordance with the invention) 10 Fructose CH.sub.3SO.sub.3H LiF 0 (not in accordance with the invention)

[0106] The 5-HMF yield is higher in the case of the combination of a dehydration catalyst such as MSA and a chloride source such as LiCl, KCl, ChCl, BetCl or TMACl in an aprotic polar solvent according to the invention compared to the dehydration catalyst alone or the chloride source alone.

[0107] The yield of unwanted products such as humins is lower in the case of the association of a dehydration catalyst such as MSA and a chloride source such as LiCl, KCl, ChCl, BetCl or TMACl in an aprotic polar solvent according to the invention compared to the dehydration catalyst alone.

[0108] The 5-HMF yield is higher in the case of the combination of a dehydration catalyst such as MSA and a chloride source such as LiCl, KCl, ChCl, BetCl or TMACl in an aprotic polar solvent according to the invention compared to the combination of a dehydration catalyst in combination with a bromide source LiBr or a fluoride source LiF.

[0109] It therefore unexpectedly appears that it is clearly advantageous to use dehydration catalysts in combination with a chloride source in an aprotic polar solvent according to the invention for the conversion of sugars into 5-HMF.